1. Field of the Invention:
This invention relates to a sound motion picture projection apparatus and more particularly to an improvement in such an apparatus which not only permits the recording and/or reproduction of sound information in synchronism with projected images but also permits automatic film loading of a sound film from an image projecting station into a sound recording and/or reproducing film path, the apparatus being provided with magnetic head means for sound recording and/or reproduction disposed along the said sound film path; and pressure pad means shiftable between a first position in which the pad means presses the film against the magnetic head means and a second position in which the pad means releases the pressing of the film.
2. Description of the Prior Art:
In the conventional sound motion picture projection apparatus of a type permitting automatic film loading, film loading is possible by actuating a continuous film feeding or advancing means such as a sprocket which is disposed along a film path for sound recording and/or reproduction. The sprocket is driven, for example, by a driving motor, together with an intermittent film feeding or advancing mechanism provided in an image projection station. Film loading occurs by shifting an operation knob provided for operation mode selection into a film loading position. After completion of film loading, image projection and synchronous sound reproduction and/or recording is possible by further shifting the operation knob into a projecting position.
In such a motion picture projection apparatus, when the operation knob is in the film loading position, a pressure pad is separated from a magnetic head to permit film loading without hindrance. A capstan which is provided behind the magnetic head along the film path for sound recording and/or reproduction and connected to a fly wheel for making film speed constant, and a pressure roller which is provided for pressing the film against the capstan, are also separated from each other to permit film loading when the operation knob is in the film loading position. When the operation knob is shifted from the film loading position to a projection position, the pressure pad and the pressure roller are brought into pressed contact respectively with the magnetic head and the capstan sandwiching the film therebetween, and then, image projection and sound reproduction or recording are commenced. With such arrangement, an operator of such a projection apparatus must check and confirm that the apparatus has been correctly loaded with the film before starting projection. The operator must devote great care to shifting the operation knob from its film loading position to the projecting position. If such shifting is made when the film has not reached the magnetic head in the film path or has not reached the continuous film feeding or advancing sprocket or under similar inadequate film feeding condition, or if other erroneous operations such as film loading with the operation knob left in the projecting position are made, the film which is fed forward from the image projection station by the intermittent feeding mechanism will be jammed and stopped by the magnetic head and the pressure pad which are already in pressed contact with each other. Such faulty operation not only makes film loading impossible but also tends to break the film.
Therefore, there has been a strong demand for an improvement in this type of sound motion picture projection apparatus to always ensure correct, automatic film loading even when poor operation is made by an operator. The present invention is directed to such improvement.